Definition of CHEK2

CHEK2: A gene on chromosome 22q that encodes a kinase enzyme and influences a person's susceptibility to breast cancer. A variant (allele) of CHEK2 that abolishes its kinase activity results in a 2-fold increase in the risk of breast cancer for women and a 10-fold increase in risk for men.

The CHEK2 kinase is at a checkpoint in the cell cycle, is activated in response to DNA damage, and prevents the damaged cell from entering mitosis.